Flow-directing cone for screw propellers



Jan. 19,. 1932. R. TUROLA ET AL 1,841,387

FLOW DIRECTJNG CONE FOR SCREW PROPELLERS Filed June 12, 1929 PA OUL 771F044 CARLO G. F S6570 mummy v Pa tentedJan. 19, 1932 UNITED STATES moor. TUROLA, or ROME, Am) CARLO (unsung A G GE 5 1 p rrow-manorme oonnron lsonnwlriiornrnnnsj Application filed'June 12, 1929, Serial'No 376,283, 15i t y Juneiso" T he present invention relates to a fixed device applicable in front ofa propeller and coaxial with same serving to impart a divergentdirection to the fluid currents which tend to converge towards the bossof the propeller so as to meet the blades of the propellers in areas close to the axis by makingthe bossvery large and giving considerable width to the blades in'order to compensate for theloss of propelling area in the central portion.

This arrangement, however, if. in various 1 tion there is applied to the eye: or bossof the propeller post a" sleeve of a" cylindrical iconical shape 6 which 'is fixed on the expanded outerskin by means of a 'suitable torwardv instances it has yielded useful results, esp'e cially in order to avoid cavitations in propel lers running at a high nuinber'of revolutions,

has not at all removeclthedrawbacks above complained of, and in addition is not readily applicable topropellers of a largediameten -and slow rotation in which the enlarged bosses would have to assume inconvenient; 7

be, audits attachmentto the{expandedouter};- Q

proportions and too heavy weights c The device fornnng the s'ubgect matter of the present invention not only provides in the propeller a fictitious enlargedboss with'the advantages mentioned above, but makes the fluid reach the areas of greater, efilcienov of the blades in larger quantity and with a ve-" 'locity and direction better calculated to inv rumpet as close to the propeller blades as; .j r

crease the propulsion efficiency.

The same device has in addition the s econ d- I ary but highly important purpose on high speed vessels, of eliminating the eddies which are formed the fiuid by the inevitable breach, of continuity existing between the stern expansion around the axis and the boss of the propeller.

In order to makethenature oftheinven- 7 tion betterunderstood' a preferred form 'of execution of same applied by way of example to a vessel with one single central propeller For this reason there is a tendency to suppress the parts of the blades-too is described below with reference to theat I tached; drawings, in which F'gil'irepresentsthe longitudinal view of v I the stern portion of the vessel with thepropel ler and the device according tothejinvention' partially shown in section; 1' r i i Fig.2; represents the saine arrangement J viewed from above in horizontal section V drawn accordlng to thewater ll'ne I'L-IIQ j A! *As ;it {is 'knownthe' stern post lot a screw "steamer QI-has im-correspondence I-with the":

shaft a-coaxial eye in: which is fixedthe tube of the ipropellershaft and-which'isthereupon l surrounded b the'hull 3 suitablyenlargedn- Betweenthe oss--ofthe propellerQfjan'd the" rea-rpacking" 5' of the said eye on the; stern pos tfthere islalways' a" superficial breach 1 continuity creating leddies 1 in the fluid cur-:1

rents; whicli following the line" ofthqhuljlf f j'tend to meet together by converging towards .theshaft'. In orderto avoidthis lconvergg ence and these eddies accordin'gto the invencollar idu'ly' formed-in order toconstitutea perfectly smooth surface with the outeriskin itself. The 'saidsleeve 6 is of ametal material 'of' wrought' orcast platens the casemayE nous welding" 'or'bj' countersunk bolts 8 or in some -other"su1table manner for" constituting a strong connection without creating faddi tional resistance owingto parts projecting heyo'nd'the smooth surfaceJ The rear portion of the sleeve 6 1s widened in a cone or Y sion of the vessel, the speed of rotation; f th propelleraand the relative 'din' ensions-of the latter'as well as of its particularjcharacteris tie data.- The said inclinationimay therefore vary'trom zero, corresponding to acylindrical I zcallyro-f said propeller, said means comprissleeve, to a very high value not usually exceeding45 It will be readily understood that the liquid currents running alongside of the I vessel and tending to meet at the stern, will by the said diverting cone 6, be deviated and made to diverge according to the arrows shown in the drawings, theresults designed by'the invention being thus attained. Simultaneously, between the sleeve and around the boss there will be formed a mass of water, which will be drawn along by the vessel in I her motion remaining stagnant in relation to 'i the propeller; this comparatively motionless mass of water will not absorb any power and will consequently constitute an artificial boss about the real boss, with an increase in efficiency and the elimination of cavity formation if any, without any addition of useless weight and space. V

Although for reasons specified the device has been described as applied to a vessel with one single central propeller, it must, of course, be understood that the said device with, the necessary variations in adaptation can be applied to vessels with multiple propellers, in

which case one diverting cone should be ar ranged for each propeller and at the ends there would be attached appendices forming a head to the lateral bosses of the sternpost or at the fmostconvenientpoints. The'invention is not contemplated as being limited to the example referred to, but also embraces all possible. applications on the bases of the fundamental principles of the'said invention.

Having now described and ascertained the natureEof our invention and in what manner.

performed we declare that V the same is to be what we claim is: a

A fluid directing-device for use with screw propellers of ships comprising a sleeve adapted to surround'the shaft on which the propeller is mounted, and having a free end ar- 2 ranged closely adjacent said propeller, and means for directing a flow of fluid acentriing" an. outwardly flared peripheral flange on the propeller end of said sleeve, and enclos ing a portion of thejhub of the-propeller.

In testimony whereof we "affix our signatures. I

- RAOUL TUROIJA. CARLO GI-USEPPE FASCETO. 

